There is conventionally known an engine control system and a vehicle including the engine control system (see, for example, Japanese Patent Publication 2002-013459). The Japanese Patent Publication discloses a method and a system (engine control system) for controlling the ignition of an engine including an alternating current (AC) generator (power generating unit) driven by rotating a crankshaft, a regulator (rectifier) half-wave rectifying a voltage output from the AC generator, an ignition plug, an ignition coil (an operational load) to which current is supplied by the regulator, and an ignition system controlling supply and cutoff of current to the ignition coil. With this engine igniting method, the ignition plug is configured to give off sparks by generating high voltage using a change in the current when the current to be supplied to the ignition coil is cut off. Furthermore, the voltage output by the regulator is obtained by half-wave rectifying the voltage from the AC generator. A waveform of the voltage output from this regulator has an angular shape including a part having a larger change in the amount of the voltage and a part having a small change in the amount of the voltage. Furthermore, the ignition system is configured to control the ignition coil to give off sparks by generating high voltage having current change by cutting off the supply of current to the ignition coil when the waveform of the voltage output from the regulator reaches a peak portion.
However, the teachings of Japanese Patent Publication 2002-013459 do not take account a number of problems. When the waveform of the voltage output by the regulator (rectifier) reaches the peak portion, the ignition system cuts off the supply of current to the ignition coil (load). Due to this, the ignition system often controls cutoff of the supply of current to the ignition coil at a timing shifted from the timing at which the waveform of the voltage output from the regulator reaches the peak due to manufacturing error such as irregular polarization of a permanent magnet of the AC generator (power generating unit). In this case, if the ignition system controls the cutoff of the supply of current to the ignition coil at a timing shifted toward the timing at which the waveform of the voltage output from the regulator reaches the part having the large change in the amount of the voltage, the ignition system executes control of the cutoff of the supply of current to the ignition coil in a state in which the voltage output from the regulator is low. In this case, the change in the amount of the current at the time of the cutoff of the supply of current to the ignition coil is small. Due to this, the necessary voltage for the ignition plug to give off sparks may not be able to be obtained. As a result, the ignition performance of the ignition plug deteriorates, so that operation of the ignition plug (load) may become unstable.